let eggChart = null;

function buildChart(eggs) {
    const tz = (typeof Auth !== 'undefined' && Auth.getUser()?.timezone) || 'UTC';
    const labels = [];
    const data   = [];

    // Build a lookup map from date string → egg count
    const eggMap = {};
    eggs.forEach(e => { eggMap[e.date] = e.eggs; });

    // Generate the last 30 days in the user's configured timezone
    for (let i = 29; i >= 0; i--) {
        const d = new Date();
        d.setDate(d.getDate() - i);
        const dateStr = d.toLocaleDateString('en-CA', { timeZone: tz });
        const [, mo, dy] = dateStr.split('-');
        labels.push(`${mo}/${dy}`);
        data.push(eggMap[dateStr] ?? 0);
    }

    const ctx         = document.getElementById('eggs-chart').getContext('2d');
    const chartWrap   = document.getElementById('chart-wrap');
    const noDataMsg   = document.getElementById('chart-no-data');
    const hasData     = data.some(v => v > 0);

    if (!hasData) {
        if (chartWrap)  chartWrap.style.display  = 'none';
        if (noDataMsg)  noDataMsg.style.display  = 'block';
        return;
    }

    if (chartWrap)  chartWrap.style.display  = 'block';
    if (noDataMsg)  noDataMsg.style.display  = 'none';

    if (eggChart) eggChart.destroy();   // prevent duplicate charts on re-render

    const green = getComputedStyle(document.documentElement).getPropertyValue('--green').trim();

    eggChart = new Chart(ctx, {
        type: 'line',
        data: {
            labels,
            datasets: [{
                data,
                borderColor:     green,
                backgroundColor: 'rgba(61,107,79,0.08)',
                borderWidth: 2,
                pointRadius: 3,
                pointHoverRadius: 5,
                fill: true,
                tension: 0.3,
            }],
        },
        options: {
            responsive: true,
            plugins: {
                legend: { display: false },
                tooltip: {
                    callbacks: {
                        label: ctx => ` ${ctx.parsed.y} eggs`,
                    },
                },
            },
            scales: {
                y: {
                    beginAtZero: true,
                    suggestedMax: 5,
                    ticks: { stepSize: 1, precision: 0 },
                },
                x: {
                    ticks: { maxTicksLimit: 10 },
                },
            },
        },
    });
}

async function loadDashboard() {
    const msg = document.getElementById('msg');

    try {
        // Fetch stats and recent eggs in parallel; eggs limited to last 30 days for chart + recent list
        const tz = (typeof Auth !== 'undefined' && Auth.getUser()?.timezone) || 'UTC';
        const start30 = new Date();
        start30.setDate(start30.getDate() - 30);
        const start30str = start30.toLocaleDateString('en-CA', { timeZone: tz });

        const [stats, budget, eggs] = await Promise.all([
            API.get('/api/stats/dashboard'),
            API.get('/api/stats/budget'),
            API.get(`/api/eggs?start=${start30str}`),
        ]);

        // Populate stat cards
        document.getElementById('s-flock').textContent    = stats.current_flock    ?? '—';
        document.getElementById('s-total').textContent    = stats.total_eggs_alltime;
        document.getElementById('s-7d').textContent       = stats.total_eggs_7d;
        document.getElementById('s-30d').textContent      = stats.total_eggs_30d;
        document.getElementById('s-avg-day').textContent  = stats.avg_eggs_per_day_30d  ?? '—';
        document.getElementById('s-avg-hen').textContent  = stats.avg_eggs_per_hen_day_30d ?? '—';
        document.getElementById('s-cpe').textContent      = fmtMoney(budget.cost_per_egg);
        document.getElementById('s-cpe-30d').textContent  = fmtMoney(budget.cost_per_egg_30d);
        document.getElementById('s-cpd').textContent      = fmtMoney(budget.cost_per_dozen);
        document.getElementById('s-cpd-30d').textContent  = fmtMoney(budget.cost_per_dozen_30d);

        // Trend chart — uses all fetched eggs, filtered to last 30 days inside buildChart
        buildChart(eggs);

        // Recent 10 collections
        const tbody  = document.getElementById('recent-body');
        const recent = eggs.slice(0, 10);

        if (recent.length === 0) {
            tbody.innerHTML = '<tr class="empty-row"><td colspan="3">No eggs logged yet. <a href="/log">Log your first collection →</a></td></tr>';
            return;
        }

        tbody.innerHTML = recent.map(e => `
            <tr>
                <td>${fmtDate(e.date)}</td>
                <td>${e.eggs}</td>
                <td class="notes">${escHtml(e.notes)}</td>
            </tr>
        `).join('');

    } catch (err) {
        showMessage(msg, `Failed to load dashboard: ${err.message}`, 'error');
    }
}

document.addEventListener('DOMContentLoaded', loadDashboard);